Diploma Thesis, TU-Vienna, 2011

The development of software for distributed systems is often carried out with middleware that provides programming abstractions to ease the implementation. Spacebased middleware systems are based on tuple spaces and allow loosely coupled components of a distributed system to coordinate over a shared data store. They provide synchronization, time and space decoupling. However, tuple spaces offer no order for the stored data objects which limits the coordination capabilities. eXtensible Virtual Shared Memory (XVSM) is a space-based middleware architecture that allows for more and flexible coordination and can be easily extended. Recently, it has been specified with a formal model in several layers, of which the lower ones have been implemented in Java as previous work.

 

This thesis describes the design and implementation of the upper layers of the formal model in MozartSpaces 2.0, the Java implementation of XVSM. They comprise the runtime, remote communication and the API. The runtime supports blocking operations with timeouts and aspects to extend the middleware functionality. Important is the fast scheduling of requests and the efficient handling of internal events for blocking operations. As example for the extensibility of XVSM we implement publish/subscribe notifications with aspects. We also present an XML protocol for the interoperable remote access to XVSM spaces and a synchronous and asynchronous API. Benchmark results show that MozartSpaces 2.0 is considerably faster than the previous version 1.0 for all operations and scales better.